<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <script src="../js/jquery-1.9.1.min.js"></script>
    <script src="../js/validate.js"></script>
    <title>Document</title>
</head>
<style>
    body {
        margin: 0;
        top: auto;
        bottom: auto;
    }

    #first {
        width: 100%;
        height: 100%;
        background-color: rgb(53, 48, 51);
        opacity: 0.5;
        position: absolute;
        z-index: 500;
    }

</style>


<body>
<div id="first">
    <button id="click">点我</button>
    <button id="prev">上一步</button>
</div>
</body>

<script>
    $(function () {
        $("#prev").click(function () {
            backToLastWindow();


        })
    })
</script>
</html>